WO2008137841A1

WO2008137841A1 - Bilaterally actuated sculling trainer

Info

Publication number: WO2008137841A1
Application number: PCT/US2008/062651
Authority: WO
Inventors: Rafael R. Medina
Original assignee: Medina Rafael R
Priority date: 2007-05-04
Filing date: 2008-05-05
Publication date: 2008-11-13
Also published as: US8109859B2; US20100240494A1; US7828706B2; CA2723332A1; US20080305934A1; CA2723332C

Abstract

An apparatus for simulating sculling 01 rowing on water includes a support frame with foot rests, a sliding seat, bilateial oars that aie rotationally coupled to a set of actuators, integrated input velocity and torque sensors, computei and computer display Each actuator incorporates a mechanical transmission, a rotational mertial mass, a variable linear and a variable non-linear damping element. The damping elements can be controlled manually or automatically by computer programs under user control.

Description

BILATERALLY ACTUATED SCULLING TRAINER

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application is related to and claims priority from U.S. Provisional Patent Application Serial No. 60/916,037, entitled: Sculling Apparatus, filed on May 4, 2007, the disclosure of which is incorporated by reference herein.

BACKGROUND

[0002] Rowing or sculling on water are enjoyable forms of recreation and exercise. In terms of exercise, the rower or sculler benefits from a full body exercise, as rowing and sculling involves exercising numerous muscle groups of the torso and upper and lower extremities. However, those who enjoy this outdoor activity are limited by proximity to a large body of water or by ambient weather conditions.

[0003] In order to have rowing or sculling always available, regardless of weather or geography, machines attempting to simulate the rowing or sculling experience have been developed in the past. However, these machines remain limited because of their use of spring based or dashpot based resistance to motion, unilateral actuation or they are cumbersome. A user may experience a semblance of rowing by moving members simulating oars however, rowing loads as reflected to the user by the machine may not be realistic or predictable. Accordingly, the rowing experience, provided by prior designs, may not simulate well the sensation of rowing or sculling on water.

SUMMARY

[0004] The disclosed subject matter provides an apparatus and method that simulates rowing or sculling on water. The disclosed subject matter simulates the sensation of rowing on water, as it models the inertial and damping properties of water. The simulation is provided by linear and non-linear dampers, working in conjunction, to provide resistance at the oars, similar to the resistance provided by water.

[0005] The disclosed subject matter is directed to an apparatus for simulating sculling or rowing on water. The apparatus includes a support frame with foot rests, a sliding seat, bilateral oars that are rotationally coupled to a set of actuators, integiated input velocity and torque sensois, computer and computei display Each actuatoi incorpoiates a mechanical tiansmission, a iotational inertial mass, a variable linear and a vanable non-linear damping element The damping elements can be conti oiled manually or automatically by computer programs under user control

[0006] The disclosed subject matter, is directed to a bilateral sculling trainer The sculling trainer includes a mam frame supporting a pair of first and second simulated oars The oars respectively rotate about first and second rotational axes that are defined by the rotational axis of first and second transmissions or actuators The first and second transmissions transmit respective rotations of the first and second simulated oars around the first and second rotational axes Incorporated within the transmissions are first and second inertial members that are respectively rotatable around the first and second rotational axes Additionally, the first and second transmissions include corresponding first and second speed changers that convert relatively high-torque, low-angular-speed rotation of the first and second simulated oars into relatively low-torque, high-angular-speed rotation of the fust and second inertial members around the first and second iotational axes

[0007] The sculling trainer also has first and second variable dampeis for lespectively resisting rotation of the first and second inertial members These first and second variable dampers include first and second variable non-lmear dampers, for example, air dampers, and first and second variable linear dampers, for example, magnetic dampers

[0008] There is disclosed an apparatus for simulating sculling, rowing or the like The apparatus includes, a mam frame for supporting first and second simulated oars, that are rotatable about respective first and second rotational axes and an actuator for receiving each of the first simulated oar and the second simulated oar Each actuator includes a dπve assembly for transmitting the rotations of the corresponding oar about the respective rotational axis, at least one angular velocity sensor for detecting the angular velocity of each oar, at least one torque sensor unit for determining the torque on each oar, and a damping system The damping system is electronically coupled with the at least one angular velocity sensor and the at least one torque sensor The damping system provides linear and non-lmear damping to create a damping load on the dnve assembly based on the detected angulai velocity and the toique on the first and second simulated oais Non-hneai damping is provided, foi example, by non-linear dampeis, such as variable an, fluid or viscous dampers, while linear damping is provided, for example, by linear dampeis, such as magnetic dampers

[0009] The apparatus may also include a processor, for example, a microprocessor The processor is programmed to receive signals corresponding to the sensed angular velocites of each oar and to receive signals corresponding to the torque on each oar, determine damping output for the damping system from these received signals, and, send signals to the damping system for controlling the linear and nonlinear damping

[0010] Also disclosed is an actuator apparatus for an object, for example, an oar or simulated oar, rotating about a rotational axis The actuator includes a drive assembly for transmitting the iotations of the object about the rotational axis, at least one angulai velocity sensor for detecting the angular velocity of the object, at least one torque sensor unit for detei mining the toique on the object, and, a damping system The damping system is electionically coupled to the at least one angular velocity sensor and the at least one torque sensor The damping system provides linear and non-lmear damping to create a damping load on the drive assembly based on the detected angular velocity and the torque on the object Non-lmear damping is provided, for example, by non-lmear dampers, such as variable air, fluid or viscous dampers, while linear damping is provided, for example, by linear dampers, such as magnetic dampers

[0011] Also disclosed is a method for simulating movement along watei The method includes receiving angular velocity and torque data from at least one simulated oar m a rotation about a rotational axis, and, determining a damping load for a drive assembly, that is coupled with the at least one simulated oar, from the received angular velocity and torque data, the damping load including non-lmear and linear damping components The drive assembly is then subjected to determined damping load, to damp the motion of the oar, to simulate the resistance of water The angular velocity and torque data, is, for example, in the form of electrical signals The non-linear damping component, for example, includes a square law function, while the linear damping component includes, for example, a linear function.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Attention is now directed to the drawings, where like reference numerals or characters indicate corresponding or like components. In the drawings:

[0013] Fig. 1 is a perspective view of an apparatus in accordance with the disclosed subject matter;

[0014] Fig. 2 is a perspective view of the drive assembly of the apparatus if Fig. 1 ; [0015] Fig. 3 is a cross sectional view of a drive assembly of the apparatus of Fig. 1, taken along line 3-3 of Fig. 2;

[0016] Figs. 4 is a perspective view of the transmission and damper assemblies within the drive assembly;

[0017] Fig. 5 is a perspective view of the damper assemblies within the drive assembly;

[0018] Fig. 6 is a cross sectional view of the damper assemblies of Fig. 5, as taken along line 5-5 of Fig. 5;

[0019] Fig. 7 is a cross sectional view of the non-linear damper assembly of Fig. 5, as taken along line 5-5 of Fig. 5; [0020] Figs. 8 is a perspective view of the of the non-linear damper assembly of the apparatus;

[0021] Fig. 9 is a cross sectional view of the non-linear damper assembly taken along line 9-9 of Fig. 8;

[0022] Fig. 10 is a cross sectional view of the linear damper assembly of Fig. 5, as taken along line 5-5 of Fig. 5;

[0023] Fig. 11 is a block diagram of the computer system of the apparatus;

10024] Fig. 12 is a is a flow diagram for the angular velocity and torque sensing; [0025] Fig. 13 is a flow diagram of the linear and non-linear damping adjustment and control; [0026] Fig 14 is a schematic block diagram of the toique and velocity load path foi the drive assembly and its majoi components in accoidance with the disclosed subject matter, and

10027] Fig 15 is a block diagram of the computer system of the appaiatus netwoiked to receive various piograms or other data entry

DETAILED DESCRIPTION OF THE DRAWINGS

[0028] Fig 1 shows the apparatus 100 of the disclosed subject matter The apparatus 100 is shown, for example, as a sculling or rowing training machine The apparatus 100 includes a longitudinal support beam 102, over which a seat 103 rolls The seat 103 includes wheels 103a on both sides of the support beam 102, that ride on parallel runners 103b The runners 103b are disposed on opposite sides of the support beam 102, on a support plate 104 The runners 103b are curved upward at their ends, to define the extent of travel for the wheels 103 a, and accordingly, limit travel of the seat 103 Foot pedals 106 extend from the sides of the longitudinal support 102 These foot pedals 106 allow the user to bi ace his feet during operation

[0029] Oars 107 are received by drive assemblies oi actuatois 200 in gimbal supports 201 Each oar 107 includes a counterweight 108, that is positioned on the respective oar 107, for example, in a fixed engagement The counterweights 108 balance and mertially simulate the mass properties of a true oar The oars 107 are maintained in a null position by a parallel arrangement of return spπngs 109 The drive assemblies 200 are maintained m position by transverse support arms 111 and diagonal support arms 112, both extending from the longitudinal support 102

[0030] A computer display 114, such as a monitor, is electronically linked, by wired or wireless links, or combinations thereof, to a computer 600, with a processoi (for example, a conventional microprocessor) 601 and an A/D (analog to digital) converter 602, shown diagramatically m Fig 11 , housed in the longitudinal support 102 In this document, "electronically linked" means electronic and/or data connections by wired or wireless links or combinations thereof The computer 600 is also electronically linked to the damping (or damper) assemblies, a non-lmear or air damper 300, and a linear or magnetic damper 500, as well as a keypad 116, through which the user inputs data, as shown diagramatically in Fig 11 [0031] Attention is now directed also to Figs 2 and 3, to detail the dnve assemblies or actuatois 200 While only one dnve assembly 200 is shown, this drive assembly 200 is lepiesentative of both drive assemblies, as the othei dnve assembly 200 is symmetric and otheiwise identical Additionally, the components of the drive assemblies 200 detailed below may be joined connected or the like by various mechanical adhesive fasteners, such as screws, bolts, seals and the like, that may not be mentioned specifically, but whose use is well known to one of skill in the art

[0032] The input end 200a of the drive assembly 200 includes the oar gimbal support 201 , that is, for example, cylindrical or of another shape sufficient to leceive a correspondingly shaped oai 107 The oar gimbal support 201 is typically pivotally mounted on a gimbal support post 202, with bushings 203, for example, of Teflon®, therebetween Strain gages (SG) 204 form the variable resistive component of a bridge circuit (detailed below) A set of strain gages 204 are integrated into each gimbal support post 202 The remainder of the bridge circuitry, along with voltage amplification circuitry (not shown) aie located on a circuit board 800 The toique sensor 802 is the assemblage of components encompassing the support posts 202, strain gages 204, bπdge and amphfiei circuits

[0033] The torque sensor 802 is electronically linked to the computei 600, as shown m Fig 1 1, via a the slip ring 21 1 /brush block 212 interface The slip ring 211 is mounted on a clutch housing 215 The brush block 212 is mounted on the drive assembly housing 216 The clutch housing 215 terminates m a cog wheel 217 Angular velocity sensor 218a , for example, a conventional chip, such as an Allegretto ATS651LSH, is mounted withm the angular velocity sensor support post 218b The support post 218b is in turn mounted on the drive assembly housing 216 The angular velocity sensor 218a is electromagnetically coupled to the cog wheel 217

[0034] The clutch housing 215 supports the gimbal support posts 202, and encases a clutch 226, that is coaxial with, and surrounds, an input dnve shaft 227 The clutch 226 and input drive shaft 227 rotate about a central axis CX The clutch 226 is designed to allow actuation in only one (a single) rotational direction The input dnve shaft 227 extends downward through a ball bearing 228

[0035] Withm the dnve assembly housing 216, the input dnve shaft 227 is rigidly coupled to input 229a of the harmonic drive 229 at the flex splme input coupling flange 230, with associated fastening mechanisms 230a Also, within the housing 216, the proximal end of the sphned output dnve shaft 234 (that rotates about the cential axis CX and is coaxial with the input drive shaft 227) is rigidly mounted to the output 229b of the harmonic drive 229 at the wave generatoi output coupling flange 231, also with associated fastening mechanisms 231a The harmonic drive 229 couples to the variable non-lmeai damper 300 via the sphned output drive shaft 234

[0036] The dnve assembly housing 216 is coupled to the damper housing 301 by an intermediate flange 235 The damper housing 301 includes air vents where the damping medium of the non-linear damper is air However, the damper housing 301 may be sealed if the damping medium for the non-lmear damper is a liquid The damper housing 301 also includes vertical support posts 301a and encloses the components that form the non-lmear damper 301 The sphned output drive shaft 234 is supported at the flange 235 by a ball bearing 236 and a seal 237, for example, an elastomeiic O-iing, labyrinth seal, or the like

[0037] Attention is now also diiected to Figs 4-9, that show the non-lmear damper (damping assembly oi mechanism) 300 m detail The sphned output dnve shaft 234 is torsionally coupled to the torque tiansfer housing assembly 400 at the proximal support plate 401 , by a female sphned coupling interface 401 a The proximal support plate 401 in turn, is rigidly coupled to the distal support plate 403 a/torque transfer cylinder 403b by the multiple support struts 402 The torque transfer cylinder 403b encloses a ball screw 304 (that rotates about the central axis CX), ball nut 305, the internally radiating spokes of a spoked ball nut support ring 307, and an end support cap 308 that houses a ball bearing 309 The ball screw 304 is supported at one end (proximal end) 304a by the ball bearing 322, encased m the distal support plate 403a, and at the other (distal) end 304b by the ball bearing 309, supported withm the end support cap 308 The first (proximal) end 304a of the ball screw 314 has a pinion gear 315 mounted on it The pinion gear 315 meshes with a tπad of radial gears 316 (only two radial gears 316 are shown in Fig 9) Each radial gear 316 is formed of coaxial gears 317a (lower or distal), 317b (upper or proximal) [0038] The lower or distal coaxial gear 317a meshes with the pinion gear 315 This gear 317a includes an integrated axle 317a', an upper or proximal portion that extends thiough the uppei 01 pioximal coaxial geai 317b The othei, lowei 01 distal portion is leceived in the distal suppoit plate 403a and is mounted with ball beatings 317c

[0039] The upper or proximal coaxial gear 317b meshes with an internal gear 318a, that is integrated into a hollow short aspect axle 319 at its internal cylindrical face An external gear 318b is integrated into the short aspect axle 319 at its external cylindrical face The short aspect axle 319 is supported proximally and distally by low profile ball bearings 320a and 320b respectively

[0040] Low profile ball bearings 320a (positioned proximally with respect to the other low profile ball bearings 320b) are supported proximally by the support plate 401, and distally by the short aspect axle 319 The distal low profile bearmg(s) 320b is supported proximally by the short aspect axle 319 and distally by the support plate 403 a

[0041] The external geai 318b meshes with a senes of multiple circumfeientially positioned sectoi pmion gears 333 Each sector pmion gear 333 is mounted centrally within the vane-axle-geai assembly 334 For example, gearing from the pmion geai 315 to the sectoi pmion gears is at a ratio ot appioximately 3 1 reduction The multiple vane-axle-gear assemblies 334 are supported at the periphery of the non-lmeai damper 300 by the pioximal support plate 401 , distal support plate 403a, and their respective sets of support bushings 337 A flywheel 342 is rigidly mounted to the proximal support plate 401

[0042] A spoked ball nut mount ring 307 is supported at its internal cylindrical face by the ball nut 305, and at its external cylindrical face by a ball bearing 351 The spoked ball nut mount ring 307 is allowed to translate axially along the slots of the of the torque transfer cylinder 403b Torque transferred to the spoked ball nut mount ring 307 from the torque transfer cylinder 403b is due to contact between the ring 346 and cylinder 403b at the slot interface

[0043] Ball bearing 351 is mounted on an externally thieaded ball bearing support cylinder 352 The externally threaded outer support cylinder 352 is in turn, coupled to the internally threaded cylindrical portion of the linear damper housing cover 501a (Fig 3) The externally threaded ball beaπng support cylinder 352 is also coupled to a pinion gear 354 mounted on a stepper motor 359 via integrated spur gear 361. The stepper motor 359 is also electronically linked to the computer 600.

[0044] A magnetic damping wheel 503 of the linear or magnetic damper 500, for example, a variable linear or magnetic damper, is rigidly supported on the torque transfer cylinder 403b. The torque transfer cylinder 403b is supported by a ball bearing 364 on the non-linear damper housing 301 (Figs. 2 and 3).

[0045] Turning also to Fig. 10, that illustrates the linear or magnetic damper (damping apparatus or assembly) 500, in detail, there is a series (set) of circumferentially positioned proximal magnets 505, that is supported at the distal external face of the damper housing 301 (Fig. 2). A series (set) of distal magnets 506 is located on the magnet support plate 508. The distal magnet support plate 508 is such that it rotates about the central axis (CX), while being confined radially and axially by the linear damping housing cover 501 (Fig. 2).

[0046] A sector spur gear 514 is mounted on the distal magnet support plate 508. The sector spur gear 514, includes gear teeth at its edge 514a, that mesh with a pinion gear 516 of a stepper motor 518. The stepper motor 518 is also electronically linked to the computer 600. The magnetic damping wheel 503 is positioned in between the set of proximal 505 and distal 506 magnets. The linear damper housing cover 501 has a central opening (not shown) that allows the torque transfer cylinder 403b unrestrained access through its center.

[0047] Attention is now directed to Figs. 1-11, to illustrate an exemplary operation of the apparatus 100, and in particular, the operation of the drive assemblies or actuators 200. When force is applied to an oar 107, a twisting moment or torque is generated and transmitted to the respective input drive shaft 227. The counterweights 108 on each oar 107 simulate the inertial properties of the suspended mass of an oar. The level of torque applied to the drive assembly 200, as well as its rotational velocity, is a function of the impedance created by the inertial and damping elements of the drive assembly 200, and the force that the user provides at the oar 107.

[0048] Linear damping is provided by the linear or magnetic dampers 500 that are under computer 600 control (Fig. 11). Non-linear damping, for example, square law damping, is provided by the non-linear dampers 300, detailed above, that aie also known as an, fluid 01 viscous dampeis The non-linear dampeis 300 aie also undei computei 600 contiol (Fig 1 1 )

[0049] Turning now to also to Fig 12, a flow chart detailing a piocess foi obtaining torque and velocity data is illustiated Initially, at block Bl , a change m resistance of the strain gage (SG) 204 caused by deflection of the gimbal support posts 202 causes a change m budge circuit output that is m turn amplified by the analog amplifier mounted on the circuit board 800, at block B2 The circuit boards 800 are mounted on the clutch housings 205 of their respective actuators 200 The amplifiei output voltage is then routed via the slip ring 21 1/ brush block 212 electrical mteiface, at block B3 to the noise filter and analog to digital converter circuits 602 of the computer 600, at block B4 This converted signal will then be used by the data analysis computei programs contained within the storage 603 or non-volatile memory of the processor, for example, a microprocessoi 601, to convert the data into real time input torque data, at block B5 [0050] At block B7, motion of the cog wheel 205 is sensed by the digital angulai velocity sensor 218a The digital angular velocity sensor 218a converts this motion into a digital signal, at block B8, and sends it to the computer 600, at block B5 This digital signal will then be used by the data analysis computei programs contained within the storage 603 and the non-volatile memory of the microprocessoi 601 , at block B5, to convert the data into real time input velocity data

[0051] The microprocessor 601 at block B5, executes the appropriate data conversion and analysis routines and displays the output data m the user selected format on the display monitor 1 14 (B6) The keypad 116 allows the user to select from a menu the program that will display the data [0052] Turning also to Fig 13, a flow chart detailing a process for varying the non-lmear damping and linear damping is illustrated Changes in linear or nonlinear damping are typically performed under computer control, through algorithms, such as those detailed below, or the like, but may also be manual This automatic or manual control requires interfacing with the computer 600 via the keypad 116 Specific sculling (rowing) routines can be selected via the keypad 116 Alternately, if the user wishes to use the machine without executing a preprogrammed routine, changes to the damping levels can be made via the keypad 116, such that the stepper motors 359 and 516 will be set to predetermined operating conditions (rotations). Still alternately, the stepper motors 359, 516 can also be set to default settings (rotations), such that computer 600 interaction is not necessary.

[0053] Initially, a rowing routine is selected from a menu of preprogrammed routines via the keypad 1 16, at block B9. During execution of a rowing program, subroutines contained within the program, typically held in the storage 603 (Fig. 1 1), will dynamically alter the linear and non-linear damping to create a dynamic change in input impedance, as seen from input drive shaft 227, at block BI l . This is then realized by the user as change in load condition at the oar that will require a change in physical output by the user to effect a desired torque output, velocity output or energy expenditure.

[0054] Linear damping is a linear function of the rotational velocity of the output drive shaft 234. Linear damping is, for example, in the form of magnetic damping and is varied when the computer 600 sends a signal to the stepper motor 518 to increment its rotation, at block Bl O. Rotation of the stepper motor 518 causes rotation of the pinion gear 516 attached to it. Rotation of the pinion gear 516 rotates the sector spur gear 514 attached to the magnet support plate 508. This is turn causes rotation of the magnet support plate 508. Rotation of the magnet support plate 508 causes a rotational shift in the distal set of magnets 506 mounted on the magnetic wheel 503, with respect to the proximal set of magnets 505, about the axial center CX of the drive assembly 200. This is reflected at block Bl 3 as a change in angular position of the magnet support plate 508.

[0055] This in turn alters the magnetic field created between the opposing proximal 505 and distal 506 sets of magnets. Hence, altering the position of one set of magnets or the flux density of the magnets changes magnetic or linear damping by altering the way the induced back voltage in the magnetic damping wheel 503 interacts with the magnetic flux lines.

[0056] The flux density of the magnets can be fixed with the use of permanent magnets or can be varied with the use of electromagnets. The amount of magnet support plate 508 rotation needed to effect a specific amount of linear damping is pre-programmed and contained within the computer control routines. [0057J Non-hneai damping is a squaie law function of the iotational velocity of the output drive shaft 234 Non-linear damping is in the foim of an 01 fluid viscous drag and is vaned when the computei 600 sends a signal to the steppei motoi 359 to increment its rotation, at block B12 This causes a ball screw 304 phase adjustment, at block B 14, that causes movements resulting m differential rotations of the fan blades 334, in block Bl 5 The processes of blocks B 12, B 14 and Bl 5 occur as follows

[0058] Incremental rotation of the stepper motor 359 causes incremental rotation of the pinion gear 354 attached to it This m turn causes incremental rotation of the sector spur gear 361 attached to the externally threaded ball bearing support cylinder outei support ring 352 Incremental rotation of the externally threaded ball bearing support cylinder outer support ring 352 causes an incremental axial translation of the ring 352 This is a result of its screw interface with the internally threaded portion of the linear dampei housing cover 501 a Incremental tianslation of the outer support ling 352 causes an incremental axial translation of the ball beaiing 351 supporting the ball nut spoke ring 346 Incremental translation of the ball bearing 351 causes an incremental axial tianslation of the spoke ring 307 Inciemental translation of the spoke ring 305 iesults in incremental axial translations of the ball nut 305 [0059] Incremental translation of the ball nut 305 causes an incremental rotation of the ball screw 304 beyond that imparted to it by its own rotational velocity High velocity rotations of the ball screw 304 is a iesult of the mterfacial coupling between the torque transfer cylinder 403b of the non-linear damper 300 and the spokes of the ball nut spoke ring 307 The incremental rotation of the ball screw 304 then causes and incremental rotation of the pinion gear 315 The incremental rotation of the pinion gear 315 causes an incremental rotation of the triad of radially oπented gears 316, resulting in a corresponding incremental rotation of the coaxial gears 317a, 317b The incremental rotation of the coaxial gears 317a, 317b translates to the internal gear 318a, causing a corresponding incremental rotation of the short aspect hollow axle 319 Incremental rotation of the short aspect hollow axle 319, and accordingly, the external gear 318b The incremental rotation of the external gear 318b causes an incremental rotation of the planetary sector pmion gear 333 mounted w ithin the vane-axle-geai assembly 334 In effect, tianslation of the ball nut 305 cieates a phase difference in iotation between the vane-axle-geai assemblies 334 and the torque tiansfei housing 400 The epicyclic geai tiain desciibed above is incorpoi ated to match the ball screw 304 displacement to vane iotation range of motion The amount of axial translation necessaiy to effect a specific amount of vane rotation for a specific amount of non-linear damping is pre-progiammed and contained within the computer control routines

[0060] As a result, the damping load is adjusted m both the non-linear 300 and linear 500 dampers, and transferred to the output drive shaft 234, to simulate damping (on an oar) caused by water This can be further augmented by the computer programs, as detailed herein, that can furthei account for the velocity of the water, slow moving, fast moving, still, or the like

[00611 The mathematical relations describing the basis foi the appaiatus 100 with its drive assemblies or actuatois 200 (also refeπed to as tiansmissions), that incoiporate inertial and lineai and non-lmeai damping elements, will now be desciibed Given a one stage mechanical tiansmission with defined properties of input and output iotational ineitia, output lineai and non-lmear damping, the equation relating input drive torque to angulai velocity and accelerations is expressed by the following equation

T₁ = (J₁ + N² Φ J_O) ø w_ιaa + (Q)₁ + N^{2 φ} (b₀ + bj)) * w_t + b_nløN³m w;

where

T₁ = input torque applied to the tiansmission J₁ = rotational inertia at the input side of the transmission

J₀ = rotational inertia at the output side of the transmission N= transmission multiplying factoi oi geai factor w, = angulai velocity at the input side of the tiansmission w_ιaa = angular acceleration at the input side of the transmission b, = drag coefficient at the input side of the transmission b₀ = drag coefficient at the output side of the transmission b_\ = linear damping coefficient at the output side of the transmission b_n\ = non-lmear damping coefficient at the output side of the transmission [0062] A schematic outline of the load path foi the above formulation is shown in Fig 14 Based on the equation above, the input toique level, lequned to obtain oi maintain a given input velocity, is sensitive to vanations in output damping levels By sensitive, it is meant that small changes in linear oi non-lmear damping will requne large changes in input torque to maintain a desned input velocity level

Accordingly, the apparatus 100 is such that fine control of damping parameters forces large changes in energy expenditure by the user in order to maintain a constant rowing velocity

[0063] Returning back to the equation previously defined, for example, design parameters may be selected representing the various equation variables, as follows input inertia, J₁ , is represented by the combined inertia of the oar 107 and its counterweight 109 and all other components that rotate at the same velocity with each stoke of the oai at the input end of the transmission 200, output inertia, J₀ , is iepresented by the combined rotational inertias of the harmonic drive 229 , output drive shaft 234, non-lineai viscous dampei assembly 300 including ball screw 304 and ball nut 305, magnetic damping wheel 503, and all other components that rotate at the same velocity as the output end of the harmonic drive 229, linear, n, , and non-lmear, n_nl , damping, are represented by the variable linear magnetic 500 and variable non-lmear fluid viscous 300 dampers respectively, transmission multiplying factor, N , is represented by the harmonic drive gear ratio

[0064] The apparatus 100 incorporates routines (including algorithms) within its storage 603 and non-volatile memory of the microprocessor 601 that convert information obtained from the angular velocity sensors 218a, and torque sensors 802, to a format usable to data manipulation, control, and three dimensional (3D) gaming/simulation routines. The control routines allow the user to adjust damping parameteis of the linear dampei 500 and the non-lmeai damper 300 as desned

[0065] The routines aie also accessed by the simulation and gaming routines to adjust the damping parameteis dynamically during program execution The data collection routines will be used to provide the user and gammg routines information regarding energy expenditure, angular velocity, force or torque input The gammg routines are included to stimulate participation in scenarios that encourage various levels of participant energy expenditure to accomplish game and/or exercise goals [0066] For example, the user can interact with the computer 600 of the apparatus 100 during a exercise session with the apparatus 100, in numerous ways Three exemplary modes of interaction are described, although numerous other interactions are also possible

[0067] In a first case, the usei defines the level ol hneai or non-linear damping directly, by sending commands via the keypad 1 16 to the computer 600 The level of damping m this case is held constant This represents an open loop contiol scheme between the user and the computer 600

[0068] In the second case, the user adjusts his woik output to meet exercise demands set by the computer program during various phases of program execution The amount of linear or non-lmear damping for each phase is programmed independent of what the user's input torque, input velocity or energy expenditure is The damping levels are quasi-statically maintained during program execution This is a closed loop control scheme between the user and the computer program but open loop control scheme within the computer program [0069] In the third case, the computer adjusts the linear or non-lmear damping levels depending on the user's work output (as determined by the torque and velocity sensor analysis routines, and what phase of program execution the program is m) The damping levels are dynamically adjusted during program execution This represents a closed loop type of feedback between the user and the computer program and closed loop feedback control within the computer program

[0070] For example, there may be a program on the computer 600, such that another sculler boater or the like may be shown on the display screen 114 This would cause the usei to attempt to keep up with, and tiy to pass, this hypothetical competitor This hypothetical competitoi is tiavehng at a iefeience velocity, that would be displayed on the scieen display 1 14 The computer 600 would be programmed such that this refeience velocity is used to adjust the damping of the non- linear 300 and lmeai 500 dampers, and accoidmgly, control the damping load on the output dnve shaft 234, to simulate the damping of the water, for this user

[0071] As shown m Fig 15, the computer 600, through its network interface 604 (Fig 11) can also be linked (by wired or wireless links) to a local 980 or wide area network 982 (the direct link shown in broken lines), for example, a public network such as the Internet, and allow multiple users to interact with each other in various simulations on a real time basis (box 984) using the apparatus 100 as a user mteiface

[0072] The processes (methods) and systems, including components thereof, herein have been desciibed with exemplary reference to specific hardware and software The processes (methods) have been described as exemplaiy, whereby specific steps and then oidei can be omitted and/or changed by persons of ordinary skill in the ait to reduce these embodiments to piactice without undue experimentation The processes (methods) and systems have been described in a manner sufficient to enable persons of ordinary skill in the art to ieadily adapt other hardware and software as may be needed to reduce any of the embodiments to practice without undue experimentation and using conventional techniques

[0073] While preferred embodiments of the disclosed subject matter have been described, so as to enable one of skill m the art to practice the disclosed subject matter, the preceding description is intended to be exemplary only It should not be used to limit the scope of the disclosure, which should be determined by reference to the following claims

Claims

What is claimed is

1 An apparatus foi simulating sculling compiising a mam frame for supporting fiist and second simulated oais, that aie rotatable about respective fust and second iotational axes, an actuator for receiving each of the first simulated oar and the second simulated oai, each actuator comprising a drive assembly configured foi tiansmitting the iotations of the corresponding oar about the respective iotational axis, at least one angular velocity sensoi for detecting the angular velocity of each oar, at least one torque sensoi unit for determining the torque on each oar, a damping system in electronic communication with the at least one angulai velocity sensor and the at least one toique sensoi, the damping system foi providing linear and non-hneai damping to ticate a damping load on the dnve assembly based on the detected angular velocity and the torque on the fiist and second simulated oais

2 The apparatus of claim 1, additionally comprising a processor programmed to receive signals corresponding to the sensed angular velocites of each oar and to receive signals corresponding to the torque on each oar, determine damping output for the damping system from these received signals, and, send signals to the damping system for controlling the linear and non-lmear damping

3 The apparatus of claim 1 , wherein the damping system includes at least one non-lmear damper and at least one linear damper

4 The apparatus of claim 1, wherein the at least one non-lmear damper and the at least one linear damper are variable dampers 5 The appaiatus of claim 3, wheiem the at least one non-linear dampei is confϊguied toi damping in accoi dance with a square law function

6 The apparatus of claim 3, wheiem the at least one linear damper is configured foi damping m accordance with a lmeai function

7 The apparatus of claim 3, wherein the at least one variable non-linear damper is selected from the group consisting of air, fluid or viscous dampers

8 The apparatus of claim 3, wherein the at least one variable linear damper includes a magnetic damper

9 The apparatus of claim 2, wherein the processor is additionally progiammed for controlling linear and non-lmeai damping to simulate resistance to rowing through water

10 The apparatus of claim 1 , wheiem each oi the fust and second simulated oars includes a counterweight

1 1 The apparatus of claim 1 , additionally comprising a seat movably coupled to the mam fi ame foi supporting a user

12 An actuator appaiatus for an object rotating about a rotational axis, comprising a drive assembly configured for transmitting the rotations of the object about the rotational axis, at least one angular velocity sensor for detecting the angular velocity of the object, at least one toique sensor unit for determining the torque on the object, a damping system in electronic communication with the at least one angular velocity sensor and the at least one torque sensor, the damping system for providing linear and non-linear damping to create a damping load on the dπve assembly based on the detected angular velocity and the torque on the object

13 The apparatus of claim 12, additionally comprising a processor piogiammed to receive signals coπesponding to the sensed angular velocites of the object and to receive signals coπesponding to the torque on the object, deteimine damping output for the damping system fiom these received signals, and, send signals to the damping system for controlling the lmeai and non-lmeai damping

14 The apparatus of claim 12, wherein the damping system includes at least one non-lmear damper and at least one linear damper

15 The apparatus of claim 12, wheiein the at least one non-lmear dampei and the at least one linear damper are variable dampers

16 The apparatus of claim 14, whei em the at least one non-lmear damper is configured for damping in accordance with a square law function

17 The apparatus of claim 14, wherein the at least one linear damper is configuied foi damping m accordance with a linear function

18 The apparatus of claim 14, wheiein the at least one variable non-lmear damper is selected fiom the gioup consisting of an, fluid oi viscous dampers

19 The apparatus of claim 14, wherein the at least one variable linear damper includes a magnetic damper

20 The apparatus of claim 13, wherein the object includes at least one simulated oar and the piocessor is additionally programmed for controlling linear and non-hneai damping to simulate resistance to rowing thiough water

21 The apparatus of claim 14, wherein the object includes at least one simulated oar

22 A method for simulating movement along water comprising receiving angular velocity and torque data from at least one simulated oar in a rotation about a rotational axis, and, determining a damping load for a dπve assembly, in communication with the at least one simulated oar, from the received angular velocity and toique data, the damping load including non-hneai and hneai damping components

23 The method of claim 22 additionally compiising subjecting the din e assembly to the deteπmned damping load

24 The method of claim 22, wherein the data is in the form of electrical signals

25 The method of claim 22, wherein the non-lmear damping component includes a square law function

26 The method of claim 22, wherein the hneai damping component includes a linear function

27 The method of claim 22, wherein the linear damping component is provided by a variable hneai dampei

28 The method of claim 27, wheiem the vanable hneai dampei includes a magnetic dampei

29 The method of claim 22, wherein the non-lmear damping component is provided by a variable non-lmear damper

30 The method of claim 29, wherein the variable non-lmear damper is selected from the group consisting of air, fluid and viscous dampers